Less Pressure than squeezing a orange to stop blood flow through the neck

many styles a black belt takes approximately three to six years of training to achieve one hour a day three times a week. 3 hrs/week 12 hrs/month, 144 hrs/yr 576 hrs

A study of seven Olympic boxers in weight classes ranging from flyweight to super heavyweight showed a range of 447 to 1,066 pounds of peak punching force. Energy transferred from punch to target varied widely depending on how heavy the boxers' hands and gloves were, how fast they punched, and how rigidly they held their wrists. The three flyweights, interestingly, delivered more oomph than all but the two super heavyweights.

-- A study of 70 boxers found elite-level fighters could punch with an average of 776 pounds of force. Another study of 23 boxers showed elite fighters were able to punch more than twice as hard as novices, the hardest hitter generating almost 1,300 pounds of force.

-- An oft-cited 1985 study of Frank Bruno, who'd go on to be WBC heavyweight champ, showed he could punch with a force of 920 pounds in the lab. Researchers extrapolated that to a real-life blow of 1,420 pounds, enough to accelerate his opponent's head at a rate of 53 g -- that is, 53 times the force of gravity.

-- Martial arts punches generally involve much less force than those in boxing. A study of 12 karate black belts showed so-called reverse punches delivered an average force of 325 pounds, with the strongest measuring 412 pounds. Short-range power punches averaged 178 pounds. Another study found martial artists needed 687 pounds of force to break a concrete slab 1.5 inches thick. One early researcher estimated karate strikes could reach 1,500 pounds, but that figure was an outlier.

Calculations
In the example of a kick traveling 30 meters per second, the force is 270 Newtons. This figure is derived from 0.45 kg, the weight of the ball, times 30 meters per second, divided by 0.05 seconds. To convert Newtons, a metric measure of force, to a second measure called kilogram-force, which measures force in units based on the force gravity exerts on 1 kg, you apply a formula that 1 kgf equals 9.81 Newtons. This yields a result of 27.52 kgf for the force of an average soccer player kicking the ball. The calculation of 270 Newtons can also be converted to a standard-measure force of about 1,200 pound-force, by dividing each Newton by 0.22481. A pound-force, also called simply a pound, also equals the gravitational force on a mass of 1 pound.

Averages
In "Biomechanical Characteristics and Determinants of Instep Soccer Kick," Eleftherios Kellis of the sports sciences department at Aristotle University in Greece compiled ball speeds from kicks reported in 27 research studies. Ball speeds ranged from a low of 14.9 meters per second in youths aged 10 to 17 to 30 meters per second for professional soccer players, with many adult amateurs able to send the ball at 25 meters per second. The pounds of force can be calculated knowing that the ball weight is constant for all the studies, with the added assumption that the shoe contact time is also fairly constant at about 0.05 seconds. Thus while professional players send the ball at 30 meters per second and 1,200 pounds of force, an average adult player sends the ball at around 25 meters per second based on a kick of 1,000 pounds of force, while average youth players may only muster a ball speed of 14.9 meters per second, indicating just 600 pounds of force.

I have heard that as low as 2-4 lbs of force can KO someone if landed cleanly on the chin

Could take Rener Gracie 8 Minutes to defeat a 285 fit guy unskilled
Up to down punching 3 to 2
up to down jiu jitsu 3 to 4

heights

Romans

Celts

Men

Women

Men

Women

Low Class Normal

5'4" 145 lbs

4'11" 120 lbs

6'1" 200

5'8" 180

Low Class Soldier

5'4" 160 lbs

4'11" 135 lbs

6'1" 219

5'8" 197

High Class Normal

5'7" 150 lbs

5'2" 125 lbs

6'6" 215 lbs

6'1" 194 lbs

High Class Soldier

5'7" 170 lbs

5'2" 140 lbs

6'6" 234 lbs

6'1" 210 lbs

Notes

Julius Caesar is Roman Aristocrachy 5'7"
Celt is 9 inches taller than Roman
Soldiers are
Height to Weight of Roman is 2.25
Height to Weight of Roman Soldier is
2.5
Height to Weight of Celt is 2.75
Height to Weight of Celt Soldier is
3
Roman Woman is 83.33% as robust as
Roman man
Celtic Woman is 90% as robust as Celtic Man
Woman is 5 inches shorter than man
Roman Aristocrachy is 3 inches taller than commoner
Celtic Aristocracy is 5 inches taller than commoner